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Rindergrippe: Detection and characterization of viral pathogens of the bovine respiratory disease complex
Project
Project code: FLI-IVD-08-Ri-0549
Contract period: 01.11.2016
- 31.03.2018
Purpose of research: Inventory & Assessment
Respiratory diseases of calves and cattle like the bovine respiratory disease (BRD) complex are one of the most relevant diseases by young cattle in an age of 3 weeks to 9 months. The regrouping of animals from several origins and herds with different health status support the developing of BRD and the severity of the disease (crowding disease). The multifactorial BRD could cause massive losses of young calves and pronounced disorders in the growth of the cattle. Beside non-infectious factors, which are favor the development of the BRD, several bacterial and viral pathogens are involved. Some of the pathogens can cause the BRD without any co-factors, but mostly different viral and bacterial pathogens are involved in the development of the disease. The bovine respiratory syncytial virus (BRSV) and the bovine parainfluenza-3 virus (BPIV-3) take here a special position because the BRD can widely cause from both viruses alone. That was the reason for the developing and the extensive use of BRSV- and BPIV-3 vaccines during the growing and mast phase of cattle. Further viral pathogens, regularly involved in the BRD, are the bovine herpesvirus 1 (BoHV-1) or the bovine viral diarrhea virus (BVDV). Based on official eradication programs in Germany both viruses are as far as possible eliminated and play only a limited role in the BRD complex in Germany. In contrast novel viruses associated with the BRD complex were detected in the last years worldwide. A significant importance of the new viruses like influenza D virus, bovine rhinitis A virus and bovine adenovirus in the BRD complex were postulated for the United States, but currently no information is available for the new viruses of the BRD complex in Germany. The situation in Germany could be complicated by the unique combination of massive vaccine campaign against BRSV and BPIV-3 and specific cattle management systems of the one hand and the successful eradication programs for BoHV-1 and BVDV of the other hand. In this “virus gap” new virus can be introduced and a novel mixture of participating viral and bacterial pathogens can develop the BRD. Based on this special situation in Germany animal disease data and conclusions from other countries cannot be only limited used. The specific problem In a big veterinary praxis, responsible for a lot of growing and mast farms in Germany, repeated cases of BRD were observed. Very often the massive clinical cases were identified in BRSV/BPIV-3 vaccinated herds. From several farmers the sense and the costs of the vaccination campaigns were critically challenged. Also for the veterinarians itself questions regarding the functionality of the used vaccines were presented. The central question is, if the circulating BRSV/BPIV-3 strains in Germany were covered by the used vaccines or are the reason for the clinical BRD cases newly or still underestimated pathogens. In the project, a novel clinical score for bovine respiratory diseased cattle was developed and applied. Based on the clinical score, diseased and clinically un-affected calves were sampled. The collected deep nasal swabs were used for the developing and validation of new screening assays for BRSV, BPIV-3 and IVD. In addition, RT-PCR assays for the molecular characterization and phylogenetic grouping of BRSV, BPIV-3 and IVD were established. Furthermore, the collected nasal swab samples were used for the establishing, development and evaluation of real-time PCR assays for BRAV, BRBV, BCoV, BAdV-3, BAstroV, Torovirus and Picobirnavirus as well as the realization of a metagenomic approach based on NGS. Based on the generated results in the project a genetic drift of BRSV and BPIV-3 in Germany could not be observed. Furthermore, the data showed that IVD is detectable in clinical affected and non-affected calves. The importance of IVD and the other pathogens in the bovine respiratory disease complex of calves should be further investigated.
Section overview
Subjects
- Animal health
- Biotechnology
